2000
#9,578
National surname rank
Recorded bearers 3,113
First available Census row
Per 100,000 1.15
Rare Last name
Twomey
An Irish surname derived from the Gaelic "Ó Tuama," meaning "descendant of Tuama" (a personal name meaning "plague").
According to the 2020 US Census Bureau surname tables, roughly 3,589 Americans carry the last name Twomey. That puts it at #9,859 in the national surname ranking, appearing at a frequency of 1.05 per 100,000 people (about 1 in 95,501 residents).
This page is the full Name Census profile for the Twomey surname. You will find the Census Bureau frequency data, a multi-census history view, an ancestry and ethnicity breakdown based on self-reported demographics, the name's meaning and origin where available, and answers to the most common questions people ask about this surname.
For British records, Name Census UK has a British surname profile for Twomey with 1881 census detail, origin facts and modern UK distribution where available.
Bearers in the US
3.6K
1 in 95,501
Census rank
#9,859
2020 decennial data
Per 100,000
1.0
Frequency rate
Recorded bearers
3.1K
rare in the US
Popularity narrative
The Census Bureau recorded 3,130 bearers of the surname Twomey in its 2020 decennial surname file. At a rate of 1.05 per 100,000 residents, it holds the 9859th position in the national surname ranking.
Among Census respondents with the surname Twomey, the largest self-reported group is White at 92.4%. The next largest groups are Hispanic (3.1%) and Two or More Races (2.9%).
Origin
Meaning and origin of Twomey
The surname Twomey originates from Ireland, specifically from the southwestern region of County Cork. It is an anglicized version of the Old Irish Gaelic name "Ó Tuama," which means "descendant of Tuama." The name Tuama is derived from the word "tuaim," meaning "a tumulus or burial mound."
The earliest recorded instances of the name Twomey can be traced back to the 12th century, where it was found in various Irish annals and manuscripts. One notable early reference is in the Annals of Inisfallen, which mentions a "Donnchad Ua Tuama" in the year 1164.
In the 16th century, the Twomey family was prominent in the barony of Muskerry, County Cork, where they were among the leading septs (clans) of the MacCarthy Reagh dynasty. During this period, the name was also spelled as "Toomey," "Twoomy," and "Twomy."
One of the earliest documented individuals with the surname Twomey was Dermot Twomey, who was born in County Cork around 1580. He was a member of the Irish military and fought in the Nine Years' War against English forces.
Another notable figure was William Twomey (1619-1688), who was a Catholic priest and scholar from County Cork. He served as the Bishop of Cork and Cloyne and was known for his opposition to the Penal Laws imposed on Catholics in Ireland.
In the 18th century, John Twomey (1714-1792) was a prominent landowner and member of the Irish Parliament, representing the constituency of Doneraile in County Cork.
During the Irish Rebellion of 1798, Michael Twomey (1770-1798) was a leader of the United Irishmen rebellion in County Cork. He was captured and executed by British forces in 1798.
In the 19th century, Michael Twomey (1805-1878) was a notable Irish Catholic priest and educator. He was the founder of St. Colman's College in Fermoy, County Cork, which became one of the leading Catholic schools in Ireland.
While the surname Twomey has its origins in County Cork, it has since spread throughout Ireland and to other parts of the world due to emigration. However, the name retains its strong connections to its historical roots in the southwestern region of Ireland.
Demographics
Ancestry and ethnicity for Twomey
Among Census respondents with the surname Twomey, the largest self-reported group is White at 92.4%. The next largest groups are Hispanic (3.1%) and Two or More Races (2.9%).
The bar chart below shows how Twomey bearers described their own race and ethnicity on the 2020 Census form. The Census Bureau groups responses into six broad categories: White, Black or African American, Hispanic or Latino, Asian and Pacific Islander, American Indian and Alaska Native, and Two or More Races. When a category has too few respondents for a given surname, the Bureau suppresses the figure to protect individual privacy, which is why some names show fewer than six slices.
Percentages are shown for every Census year so the breakdown stays comparable over time. When the source file also includes raw headcounts, Name Census shows those alongside the percentages in the legend.
Keep in mind that these are self-reported numbers. A person's surname does not determine their race or ethnicity, and the distribution you see here reflects the specific population who happened to carry the Twomey surname at the time of the 2020 Census, not any inherent property of the name itself.
- White92.4% · 2,892
- Hispanic or Latino3.1% · 98
- Two or more races2.9% · 90
- Asian and Pacific Islander1.0% · 30
- Black or African American0.5% · 16
- American Indian and Alaska Native0.1% · 4
Timeline
Historical Census data for Twomey
Twomey appears in 3 published Census surname files: 2000, 2010, 2020. The cards below show how the name's rank and bearer count changed across each release.
2010
#9,949
National surname rank
Recorded bearers 3,245
+132 bearers (+4.2%)
Per 100,000 1.10
Rank movement Down 371 places
2020
#9,859
National surname rank
Recorded bearers 3,130
-115 bearers (-3.5%)
Per 100,000 1.05
Rank movement Up 90 places
| Year | Rank | Count | Per 100K | Count change | Rank change |
|---|---|---|---|---|---|
| 2000 | #9,578 | 3,113 | 1.15 | First available Census row | First available Census row |
| 2010 | #9,949 | 3,245 | 1.10 | +132 bearers (+4.2%) | Down 371 places |
| 2020 | #9,859 | 3,130 | 1.05 | -115 bearers (-3.5%) | Up 90 places |
For 2020, the Census Bureau published race and Hispanic-origin columns as counts rather than percentages. Name Census converts those counts back into shares so the ancestry section stays comparable with the older surname files.
Year on year
2010 vs 2020 Census
How has the Twomey surname changed between Census years? The chart shows bearer count side by side, and the table compares rank, count, and frequency.
Census year comparison
20102020
| Metric | 2010 | 2020 | Change |
|---|---|---|---|
| Rank | #9,949 | #9,859 | 0.9% |
| Count | 3,245 | 3,130 | -3.5% |
| Per 100K | 1.10 | 1.05 | -4.8% |
Between the 2010 and 2020 Census, the number of Twomey bearers went from 3,245 to 3,130 (-3.5% change). The surname moved up 90 positions in the national ranking, going from #9,949 to #9,859.
FAQ
Twomey surname: questions and answers
How many people in the U.S. have the surname Twomey?
Name Census estimates that about 3,589 living Americans carry the surname Twomey. Using the current population baseline, that works out to roughly 1 in 95,501 residents.
How common is Twomey?
Twomey ranks #9,859 in the 2020 Census surname tables and is classified on this site as "Rare." The Census recorded the name at a frequency of 1.05 per 100,000 residents, which is about 1 people out of every 100,000.
How many people with this surname were counted in the Census?
The raw 2020 Census file counted 3,130 people with the surname Twomey. That is different from the site's living-bearer estimate (3,589), which projects the surname's present-day count by applying the Census frequency rate to the current U.S. population.
What does 1.05 per 100,000 actually mean?
It is the Census Bureau's normalized frequency measure. A rate of 1.05 per 100,000 means that if you picked a random group of 100,000 U.S. residents, you would expect about 1 of them to have the surname Twomey.
Has Twomey become more or less common over time?
Between 2010 and 2020, the surname Twomey went from 3,245 recorded bearers to 3,130. That is a decrease of 115 (-3.5%). In the national ranking it rose from #9,949 to #9,859.
What does the Census say about the background of Twomey?
Among Census respondents with the surname Twomey, the largest self-reported group is White at 92.4%. The next largest groups are Hispanic (3.1%) and Two or More Races (2.9%). These figures come from the 2020 Census Bureau surname tables, based on how respondents described their own race and ethnicity.
Which group reports this surname most often?
White is the largest self-reported group for the surname Twomey in the 2020 Census, accounting for 92.4% (2,892 people in the source table).
What is the full ancestry breakdown?
Twomey appears across multiple self-reported groups in the Census data. The largest shares in the 2020 file are White (92.4%), Hispanic (3.1%), Two or More Races (2.9%). For 2020, the source file also published raw headcounts for each group, which is why this page can show both percentages and counts in the ancestry section.
Is this page using the latest Census data?
Yes. This page is using the latest surname file currently loaded on Name Census, which is 2020. The historical section above also keeps any older Census surname entries we have for Twomey (2000, 2010, 2020).
Does the Census include every surname?
No. The Census Bureau only publishes surnames that appeared at least 100 times in a given decennial Census. That means very rare surnames are excluded entirely, and a surname can appear in one Census release but disappear from a later one if it falls below the reporting threshold.
Why don't the ancestry percentages always add up to exactly 100%?
There are two main reasons: rounding and suppression. The Census Bureau rounds published values, and it may suppress very small cells to protect privacy. For 2020, the Bureau also published raw group counts rather than direct percentages, so Name Census converts those counts back into shares for comparability across census years.
What does Twomey mean?
An Irish surname derived from the Gaelic "Ó Tuama," meaning "descendant of Tuama" (a personal name meaning "plague"). The fuller origin note on this page goes into more detail.
Where does the surname data come from?
All surname statistics on Name Census are drawn from the US Census Bureau's decennial surname frequency tables. These files list every surname that appeared 100 or more times in the 2020 Census, along with a count, a per-100,000 rate, and a self-reported demographic breakdown. You can read the full explanation on our methodology page.
How does Name Census estimate living bearers?
For surnames, Name Census does not age cohorts the way it does for first names. Instead, it takes the Census Bureau's published frequency for Twomey (1.05 per 100,000) and applies that rate to the current U.S. resident population to estimate how many living Americans have the surname today.
How common is the surname Twomey?
Want to know how common the surname Twomey is? HowManyOfMe.org, our sister site, puts the living-bearer count front and centre.